Green councillors in Oxford are claiming that extreme weather and serious flooding will get worse as the impact of climate change becomes more intense.

The Botley road railway bridge suffers frequent flooding problems

They spoke out after a storm on Wednesday brought monsoon conditions to Oxford for the second time in 24 hours.

The Greens are calling for measures to reduce pollution in the atmosphere which is harming the ozone layer and, experts believe, leading to dramatic changes in weather conditions.

The hour-long downpour on Wednesday caused chaos across the city, particularly on the Eastern Bypass, which was flooded for the second time in two days. But, despite the downpours, Thames Water said yesterday it could not rule out a hosepipe ban this summer because there had been so little rainfall in the region over the winter.

Craig Simmons, leader of the city council's Green group, said: "Climate change is characterised by more extreme weather patterns, exactly like the torrential rain that Oxford has been experiencing in the past few days.

"As Greens have been warning for decades, unless we introduce radical measures to deal with the problem, the economic and social damage caused by a runaway climate will become worse and worse." In 2003, Mr Simmons contributed to a report on likely impacts of climate change in the South East entitled Global Warming, Local Warmin', co-written by Euro MP and Oxfordshire Green Party member Dr Caroline Lucas and climate expert Dr Paul Williams.

The report warned that climate change would hit the south east of England hard. It predicted serious economic damage as a result of flooding and extreme weather conditions.

Since the publication of the report, areas of Oxford such as Botley Road have suffered serious flooding damage and East Oxford was inundated with rainwater this week.

Matt Sellwood, who is deputy leader of the green group, added: "We don't have to accept climate change.

"The Greens have been putting forward a number of initiatives to deal with the threat, such as installing renewable energy as a matter of course on all council buildings and investing millions in energy-efficiency programmes.

"We call on all political parties to get behind these measures before it's too late, and prevent future misery for thousands of Oxford residents."

Thames Water said last night that the possibility of a hosepipe ban this summer could not be ruled out despite the recent downpours.

Spokesman Andrew Boyd said: "The rainfall in the past few days certainly helps, but we're still predicting below average rainfall for June and we have now had eight consecutive months of below average rainfall."

County council engineers have promised to check drains in the city centre after traders complained of huge puddles forming, flooding St Giles and damaging the cellar of a newsagents.